First of all I would like to say great job on the code. You really seem to know your stuff.

Ive been messing around with the NXT and robotc for about a year now, and now Im attempting to create a self parking robot that uses 2 L.E.D.'s and 2 ir seeker sensors.

Im curious to know how to get the seeker sensors to pick up and work out the exact frequancy of an l.e.d. source. Your code is helping but Im struggling to get my robot to identify what the frequancy for each led is by displaying there values (ont the NXT screen or on the computr screeen). If I could do that then I could begin to write a program that would allow the robot to navigate towards them.

First of all I would like to say great job on the code. You really seem to know your stuff.

Ive been messing around with the NXT and robotc for about a year now, and now Im attempting to create a self parking robot that uses 2 L.E.D.'s and 2 ir seeker sensors.

Im curious to know how to get the seeker sensors to pick up and work out the exact frequancy of an l.e.d. source. Your code is helping but Im struggling to get my robot to identify what the frequancy for each led is by displaying there values (ont the NXT screen or on the computr screeen). If I could do that then I could begin to write a program that would allow the robot to navigate towards them.

Have you got any suggestions???

Cheers Andy

Thanks for the compliment. I am not sure what you mean by frequency of the light. Are you intermittently blinking them? Is one blinking at, say, 10 Hz and the other at something like 20Hz? If this is the case then you could check the IR seekers at at least twice the fastest frequency, that's 40Hz, in this case. Then you should count the length of each pulse from the different LEDs. It is not unlike reading a wheel encoder

First of all I would like to say great job on the code. You really seem to know your stuff.

Ive been messing around with the NXT and robotc for about a year now, and now Im attempting to create a self parking robot that uses 2 L.E.D.'s and 2 ir seeker sensors.

Im curious to know how to get the seeker sensors to pick up and work out the exact frequancy of an l.e.d. source. Your code is helping but Im struggling to get my robot to identify what the frequancy for each led is by displaying there values (ont the NXT screen or on the computr screeen). If I could do that then I could begin to write a program that would allow the robot to navigate towards them.

Have you got any suggestions???

Cheers Andy

Thanks for the compliment. I am not sure what you mean by frequency of the light. Are you intermittently blinking them? Is one blinking at, say, 10 Hz and the other at something like 20Hz? If this is the case then you could check the IR seekers at at least twice the fastest frequency, that's 40Hz, in this case. Then you should count the length of each pulse from the different LEDs. It is not unlike reading a wheel encoder

Regards,Xander

Thats a good idea. Ive been trying to think of how to have two different signals coming from the LED's. I was thinking of something as simple different LED Brightness levels. But I need to work out how to read the LED light source using the nxt and ir seeker, so that I can then test different methods for defining the LED. Thats why I wandering If you could advise me on how to get the ir seeker to read the LED source (say from the robocup jr ball, which i got to test it). If I can see what type of readings the ir seeker picks up I can then work out how Im gonna differentiate netween them.

[quote="andynalley"Thats a good idea. Ive been trying to think of how to have two different signals coming from the LED's. I was thinking of something as simple different LED Brightness levels. But I need to work out how to read the LED light source using the nxt and ir seeker, so that I can then test different methods for defining the LED. Thats why I wandering If you could advise me on how to get the ir seeker to read the LED source (say from the robocup jr ball, which i got to test it). If I can see what type of readings the ir seeker picks up I can then work out how Im gonna differentiate netween them.

Cheers[/quote]Brightness is also a dependent on distance, so how will you tell the difference between a dim LED close by and a bright LED that's far away? Pulsing the LEDs is by far the most fool-proof method to distinguish between different sources. In the absence of actually owning one of these sensor I am going to have to guess that you just hold the ball in front of it and move it about and check the different readings as they come out of the sensor. The Robocup Jr ball doesn't blink at 10 or 20 Hz, as far as I am aware of so it is a constant source of IR light. It's basically an array of many IR LEDs. Did I not include a little test program with the driver?

[quote="andynalley"Thats a good idea. Ive been trying to think of how to have two different signals coming from the LED's. I was thinking of something as simple different LED Brightness levels. But I need to work out how to read the LED light source using the nxt and ir seeker, so that I can then test different methods for defining the LED. Thats why I wandering If you could advise me on how to get the ir seeker to read the LED source (say from the robocup jr ball, which i got to test it). If I can see what type of readings the ir seeker picks up I can then work out how Im gonna differentiate netween them.

Cheers

Brightness is also a dependent on distance, so how will you tell the difference between a dim LED close by and a bright LED that's far away? Pulsing the LEDs is by far the most fool-proof method to distinguish between different sources. In the absence of actually owning one of these sensor I am going to have to guess that you just hold the ball in front of it and move it about and check the different readings as they come out of the sensor. The Robocup Jr ball doesn't blink at 10 or 20 Hz, as far as I am aware of so it is a constant source of IR light. It's basically an array of many IR LEDs. Did I not include a little test program with the driver?

Regards,Xander[/quote]

Yeh ya did include the test program. Ive been trying to use it for ages with the test ball but it doesnt do anything. Whats it meant to do??? Havent you specified it to respond to a certain Lumen, meaning that if my ball producing that Lumen it wont do anything???

Ok no probs. Well Ive just slightly overcome my own stupidity and got your test program working. Is there any lumen value set in your driver software or is it litterally just drivers telling the nxt what type of data it should be picking up. If so, how would I define 2 ir sensors, one in port 1(s1) one in ort 2(s2). Would this work.

Ok no probs. Well Ive just slightly overcome my own stupidity and got your test program working. Is there any lumen value set in your driver software or is it litterally just drivers telling the nxt what type of data it should be picking up. If so, how would I define 2 ir sensors, one in port 1(s1) one in ort 2(s2). Would this work.

I do no processing of any kind of the data. What you get is what the sensor provided the driver. I use standard I2C transactions to retrieve this data. There is no magic or transmogrification of any kind involved The data returned is not a unit like "lumens", it's just a relative strength value or a direction value, depending on what function is called.

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